In this work, we investigated from a theoretical point of view the dynamics of the energy transfer process from the ligand to Eu(III) ion for 12 isomeric species originating from six different complexes differing by nature of the ligand and the total charge. The cationic complexes present the general formula [Eu(L)(H₂O)₂]⁺ (where L = bpcd^2- = N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate; bQcd^2- = N,N'-bis(2-quinolinmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate; and bisoQcd^2- = N,N'-bis(2-isoquinolinmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate), while the neutral complexes present the Eu(L)(H₂O)₂ formula (where L = PyC3A^3- = N-picolyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetate; QC3A^3- = N-quinolyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetate; and isoQC3A^3- = N-isoquinolyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetate). Time-dependent density functional theory (TD-DFT) calculations provided the energy of the ligand excited donor states, distances between donor and acceptor orbitals involved in the energy transfer mechanism (R_L), spin-orbit coupling matrix elements, and excited-state reorganization energies. The intramolecular energy transfer (IET) rates for both singlet-triplet intersystem crossing and ligand-to-metal (and vice versa) involving a multitude of ligand and Eu(III) levels and the theoretical overall quantum yields (ϕ_ovl) were calculated (the latter for the first time without the introduction of experimental parameters). This was achieved using a blend of DFT, Judd-Ofelt theory, IET theory, and rate equation modeling. Thanks to this study, for each isomeric species, the most efficient IET process feeding the Eu(III) excited state, its related physical mechanism (exchange interaction), and the reasons for a better or worse overall energy transfer efficiency (η_sens) in the different complexes were determined. The spectroscopically measured ϕ_ovl values are in good agreement with the ones obtained theoretically in this work.

The coordination features and signaling of a L-lactate ion by a [Tb(bpcd)]⁺ (bpcd = N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N′-diacetate) complex have been investigated by means of a combination of techniques, including total luminescence, calorimetry and circularly polarized luminescence. The L-lactate/[Tb(bpcd)]⁺ association constant, determined by both luminescence titration and isothermal titration calorimetry, indicates a weak interaction (log K = 1.3–1.45) between the analyte and both enantiomers of the complex. The theoretical DFT calculations suggest that the most likely coordination of L-lactate to the possible stereoisomers of the [Tb(S,S-bpcd)]⁺ complex (trans-O,O or trans-N_py,N_py) is one involving a hydroxyl group. The results of [Tb(rac-bpcd)]⁺ as a chiroptical luminescent probe of L-lactate underline the peculiar role of the chiral 1,2-diaminocyclohexane (DACH) backbone. Indeed, the target anion is capable of inducing CPL activity in the racemic mixture of Tb complexes containing DACH-based ligands. The same is not observed for the achiral analogue [Tb(bped)]⁺ (bped = N,N′-bis(2-pyridylmethyl)ethylenediamine-N,N′-diacetate) complex, likely because of the flexibility of the ethylenic group which allows an interconversion between different isomers which produces a null net CPL activity. Thanks to the differential quantum yield of the two diastereomeric species (R,R)-L and (S,S)-L, one can use the racemic complex to reveal L-lactate by measuring the induced CPL spectrum. Interestingly, this has been demonstrated in a commercial complex solution for medical use, containing several electrolytes, namely Ringer's lactate.

The ability of carbon-based nanomaterials (CNM) to interact with a variety of pharmaceutical drugs can be exploited in many applications. In particular, they have been studied both as carriers for in vivo drug delivery and as sorbents for the treatment of water polluted by pharmaceuticals. In recent years, the large number of experimental studies was also assisted by computational work as a tool to provide understanding at molecular level of structural and thermodynamic aspects of adsorption processes. Quantum mechanical methods, especially based on density functional theory (DFT) and classical molecular dynamics (MD) simulations were mainly applied to study adsorption/release of various drugs. This review aims to compare results obtained by theory and experiments, focusing on the adsorption of three classes of compounds: (i) simple organic model molecules; (ii) antimicrobials; (iii) cytostatics. Generally, a good agreement between experimental data (e.g. energies of adsorption, spectroscopic properties, adsorption isotherms, type of interactions, emerged from this review) and theoretical results can be reached, provided that a selection of the correct level of theory is performed. Computational studies are shown to be a valuable tool for investigating such systems and ultimately provide useful insights to guide CNMs materials development and design.

The monofunctional platinum drug phenanthriplatin (phenPt) blocks the replication of cancer cells even if it reacts with only one guanine base. However, there is still insufficient experimental data to improve its cytotoxicity and all previously proposed chemical modifications of the parent structure have resulted in a loss of activity. We use theoretical tools to illustrate the key steps in the biological mechanisms of phenPt; that is, its activation in water and the subsequent attack on DNA. Our simulations suggest that the measured kinetic parameters, which are based on free nucleobases in solution, need to be reinterpreted because the self-assembled stacked reactive adduct formed in the reaction is inaccessible in real DNA. The constants reported here will help guide future work in the synthesis of anticancer platinum drugs.